Patent GB-827645-A (GB)
Title: Improvements in the formation of aldehyde resins
Inventor: RYAN JOHN JAMES
IPC: C08L61/06
Filed: 1955-04-29
Abstract: An aqueous solution contains the ingredients of a pre-condensate of an aldehyde resin, the formation of which is catalysed by acid, and an acid salt of a polybasic acid, having a first dissociation constant of at least 10-6 with a metal of which a less acid salt with the same acid is precipitated before the said acid salt on removal of water from the solution. Precipitation of the less acid salt raises the acidity of the solution and catalyses the formation of the resin. The acid salt may be formed in situ from an acid salt, e.g. alkali metal or ammonium acid salt, of the polybasic acid together with a salt of an acid stronger than the polybasic acid (e.g. hydrochloric, sulphuric or nitric acid) with the desired metal.  In the case of magnesium dihydrogen phosphate or salts which will produce it in situ, a hydrate of magnesium monohydrogen phosphate is precipitated on heating the solution without evaporation to 70 DEG  C., thereby causing a rise in the acidity of the solution and catalysis of the resin formation.  Aldehyde resins specified are urea-formaldehyde and their ethers, melamine-formaldehyde and their ethers, and phenol-formaldehyde.  Examples of acid salts given are magnesium, calcium, strontium, nickel and lithium dihydrogen phosphates, calcium hydrogen phosphate, calcium or p  strontium hydrogen malonate, calcium hydrogen malate, barium or calcium hydrogen maleate, strontium hydrogen tartrate and calcium hydrogen succinate.  Examples of mixed salts to produce the desired one in situ are sodium dihydrogen phosphate with magnesium, calcium, lithium or strontium chloride or magnesium or nickel sulphate; sodium hydrogen maleate with barium or calcium chloride; sodium hydrogen malonate with strontium or calcium chloride; disodium hydrogen phosphate with lithium chloride; potassium hydrogen phosphite with calcium chloride; sodium hydrogen succinate with calcium chloride; sodium hydrogen tartrate with strontium chloride; sodium hydrogen maleate with calcium chloride.  If desired, an agent capable of forming a soluble complex with the selected metal ions may be added to the solution. Examples are ethylene diamine tetra-acetic acid, nitrilotriacetic acid, cyclohexylene tetra-acetic acid and alkali metal salts of these acids.  If the initial pH of the solution is too low for the desired stability, buffering agents, e.g. an alkali metal monohydrogen phosphate or a tri-alkali metal phosphate, ammonia or an organic base, or an alkali metal hydroxide or borate may be added to the solution.  The solutions of the invention may be used for the treatment, e.g. delustring or creaseproofing, or fibres, yarns or fabrics.  Examples 1-15 employ the invention for the production of crease-resistant cotton or viscose fabrics.  Example 16 uses an aqueous solution of methylol urea containing sodium dihydrogen phosphate and calcium chloride for delustreing a viscose fabric, and Example 17 is similar using a mixture of sodium dihydrogen phosphate and magnesium sulphate.  Example 18 uses the invention for the production of a viscose film with lustrous printed areas on a delustred ground and good crease resistance.  Specification 467,480 is referred to.ALSO:An aqueous solution contains the ingredients of an aldehyde resin, the formation of which is catalysed by acid (or a pre-condensate thereof) and an acid salt of a polybasic acid, having a first dissociation constant of at least 10-6 with a metal of which a less acid salt with the same acid is precipitated before the said acid salt on removal of water from the solution. Precipitation of the less acid salt raises the acidity of the solution and catalyses the formation of the resin.  The acid salt may be formed in situ from an acid, e.g. alkali metal or ammonium, salt of the polybasic acid together with a salt of an acid stronger than the polybasic acid (e.g. hydrochloric, sulphuric or nitric acid) with the desired metal. In the case of magnesium dihydrogen phosphate or salts which will produce it in situ, a hydrate of magnesium monohydrogen phosphate is precipitated on heating the solution without evaporation to 70 DEG C. thereby causing a rise in the acidity of the solution and catalysis of the resin formation.  Aldehyde resins specified are urea-formaldehyde and their ethers, melamineformaldehyde and their ethers, and phenolformaldehyde.  Examples of acid salts given are magnesium, calcium, strontium, nickel and lithium dihydrogen phosphates, calcium hydrogen phosphite, calcium or strontium hydrogen malonate, calcium hydrogen malate, barium or calcium hydrogen maleate, strontium hydrogen tartrate and calcium hydrogen succinate. Examples of mixed salts to produce the desired one in situ are sodium dihydrogen phosphate with magnesium, calcium, lithium or strontium chloride, or magnesium or nickel sulphate; sodium hydrogen maleate with barium or calcium chloride; sodium hydrogen malonate with strontium or calcium chloride; disodium hydrogen phosphate with lithium chloride; potassium hydrogen phosphite with calcium chloride; sodium hydrogen succinate with calcium chloride; sodium hydrogen tartrate with strontium chloride; sodium hydrogen malate with calcium chloride.  If desired, an agent capable of forming a soluble complex with the selected metal ions may be added to the solution.  Examples are ethylene diamine tetra-acetic acid, nitrilo triacetic acid, cyclohexylene tetra-acetic acid and alkali metal salts of these acids.  If the initial pH of the solution is too low for the desired stability, buffering agents, e.g. an alkali metal monohydrogen phosphate or a tri-alkali metal phosphate, ammonia or an organic base, alkali metal hydroxide or borate may be added to the solution. The solutions of the invention may be used for the treatment, e.g. delustring of fibres, yarns, fabrics or paper or as adhesives or bonding agents, e.g. in moulding powders or for glass fibres, or for laminating.  A number of curves show the relationship between pH value and molar concentration of salt systems according to the invention.  Most of the examples relate to the treatment of textiles (see Group IV (c)).  In Example 22 paper was boiled in dilute HCl, and the cellulose mash neutralized, dried, mixed with urea-formaldehyde bonding syrup containing a mixture of dissolved magnesium sulphate and sodium dihydrogen phosphate, and ground to yield a moulding powder. Example 23 employs a phenol formaldehyde bonding syrup containing magnesium perchlorate and sodium dihydrogen phosphate for bonding together plywood veneers.  Specification 467,480 is referred to.